/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#if !defined(THREAD_H_INCLUDED)
+#ifndef THREAD_H_INCLUDED
#define THREAD_H_INCLUDED
-#include <cstring>
+#include <atomic>
+#include <bitset>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+#include <vector>
-#include "lock.h"
+#include "material.h"
#include "movepick.h"
+#include "pawns.h"
#include "position.h"
#include "search.h"
+#include "thread_win32.h"
-const int MAX_THREADS = 32;
-const int MAX_ACTIVE_SPLIT_POINTS = 8;
-
-struct SplitPoint {
-
- // Const data after splitPoint has been setup
- SplitPoint* parent;
- const Position* pos;
- Depth depth;
- bool pvNode;
- Value beta;
- int ply;
- int master;
- Move threatMove;
-
- // Const pointers to shared data
- MovePicker* mp;
- SearchStack* ss;
-
- // Shared data
- Lock lock;
- volatile int64_t nodes;
- volatile Value alpha;
- volatile Value bestValue;
- volatile int moveCount;
- volatile bool betaCutoff;
- volatile int slaves[MAX_THREADS];
+
+/// ThreadBase struct is the base of the hierarchy from where we derive all the
+/// specialized thread classes.
+
+struct ThreadBase : public std::thread {
+
+ ThreadBase() { exit = false; }
+ virtual ~ThreadBase() = default;
+ virtual void idle_loop() = 0;
+ void notify_one();
+ void wait(std::atomic_bool& b);
+ void wait_while(std::atomic_bool& b);
+
+ Mutex mutex;
+ ConditionVariable sleepCondition;
+ std::atomic_bool exit;
+};
+
+
+/// Thread struct keeps together all the thread related stuff like locks, state,
+/// history and countermoves tables. We also use per-thread pawn and material hash
+/// tables so that once we get a pointer to an entry its life time is unlimited
+/// and we don't have to care about someone changing the entry under our feet.
+
+struct Thread : public ThreadBase {
+
+ Thread();
+ virtual void idle_loop();
+ void search(bool isMainThread = false);
+
+ Pawns::Table pawnsTable;
+ Material::Table materialTable;
+ Endgames endgames;
+ size_t idx, PVIdx;
+ int maxPly, callsCnt;
+ std::atomic_bool searching, resetCallsCnt;
+
+ Position rootPos;
+ Search::RootMoveVector rootMoves;
+ Depth rootDepth;
+ HistoryStats history;
+ MovesStats counterMoves;
+ Depth completedDepth;
};
-// ThreadState type is used to represent thread's current state
-enum ThreadState
-{
- THREAD_INITIALIZING, // thread is initializing itself
- THREAD_SEARCHING, // thread is performing work
- THREAD_AVAILABLE, // thread is waiting for work
- THREAD_BOOKED, // other thread (master) has booked us as a slave
- THREAD_WORKISWAITING, // master has ordered us to start
- THREAD_TERMINATED // we are quitting and thread is terminated
+
+/// MainThread is a derived classes used to characterize the the main one
+
+struct MainThread : public Thread {
+ MainThread() { thinking = true; } // Avoid a race with start_thinking()
+ virtual void idle_loop();
+ void join();
+ void think();
+ std::atomic_bool thinking;
};
-struct Thread {
- Lock sleepLock;
- WaitCondition sleepCond;
- volatile ThreadState state;
- SplitPoint* volatile splitPoint;
- volatile int activeSplitPoints;
- SplitPoint splitPoints[MAX_ACTIVE_SPLIT_POINTS];
+
+/// ThreadPool struct handles all the threads related stuff like init, starting,
+/// parking and, most importantly, launching a thread.
+/// All the access to shared thread data is done through this class.
+
+struct ThreadPool : public std::vector<Thread*> {
+
+ void init(); // No constructor and destructor, threads rely on globals that should
+ void exit(); // be initialized and valid during the whole thread lifetime.
+
+ MainThread* main() { return static_cast<MainThread*>(at(0)); }
+ void read_uci_options();
+ void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
+ int64_t nodes_searched();
};
-#endif // !defined(THREAD_H_INCLUDED)
+extern ThreadPool Threads;
+
+#endif // #ifndef THREAD_H_INCLUDED